For this equation: I don't care what the answer is, I need to know how to solve for it. Thanks. Which of the following sets shows all the numbers from the set {3, 4, 5, 6} that are part of the solution to the equation 5x + 4 < 29? (4 points)

{4, 5, 6}
{3, 4, 5}
{3, 4}
{3}

Explanation:

Solve the inequality for x.

5x + 4 < 29

5x < 29-4

5x < 25

x < 25/5

x < 5

I subtracted 4 from both sides (step 2). Then I divided both sides by 5 to fully isolate x (step 4). The inequality sign stays the same the entire time.

Since x < 5, this means the original set {3,4,5,6} becomes {3,4} since these values make x < 5 a true statement. In other words, we erase 5 and 6 because something like 6 < 5 is false.

That's why {3, 4} is the final answer.

An alternative method is to go through the set {3,4,5,6} and plug those items one by one into the original inequality. If you get a true result, then it's part of the answer.

Let's try x = 3

5x + 4 < 29

5(3) + 4 < 29

15+4 < 29

19 < 29

We get a true statement at the end, so x = 3 is part of the solution set. A similar story happens for x = 4 as well.

If we tried x = 5, then,

5x + 4 < 29

5(5) + 4 < 29

25 + 4 < 29

29 < 29

which is false. No number is bigger than itself (or smaller than itself). Therefore, x = 5 is crossed out of the original set. You should get a false statement for x = 6, which means we'll kick this value out as well.